A NEW NEMATODE, OSTERTAGIA BULLOSA, 

PARASITIC IN THE ALIMENTARY 

TRACT OF SHEEP 



BY 



BRAYTON HOWARD RANSOM 

Assistant Custodian, Helminthological Collections, United States National Museum 
AND 

MAURICE C. HALL 

Assistant Zoologist, Bureau of Animal Industry, United States Department of Agriculture 



No. 1892. — From the Proceedings of the United States National Museum, 
Vol. 42, pages 175-179 

Published February 28, 1912 




Washington 

Government Printing Office 

1912 



A NEW NEMATODE, OSTERTAGIA BULLOSA, 

PARASITIC IN THE ALIMENTARY 

TRACT OF SHEEP 



BY 



BRAYTON HOWARD RANSOM 

Assistant Custodian, Helminthological Collections, United States National Museum 
AND 

MAURICE C. HALL 

Assistant Zoologist, Bureau of Animal Industry, United States Department of Agriculture 



No. 1892. — From the Proceedings of the United States National Museum, 
Vol. 42, pages 175-179 

Published February 28, 1912 




Washington 

Government Printing Office 

1912 






n AF ft- 



A NEW NEMATODE, OSTERTAGIA BULLOSA, PARASITIC 
IN THE ALIMENTARY TRACT OK SIIIOFOP. 



By.BRAYTON Howard Ransom, 

Assistant Custodian, 1 Ichninthological Collection*, thiiled States National Museum, 



Maurice C. Hall, 

Assistant Zoologist, Bureau of A trivial Industry, United Stales Department of Agriculture. 



The nematode described in this paper was first collected by the 
junior author at an abattoir in Colorado Springs, Colorado, April 28, 
1911. Comparison with the descriptions of species given in Ransom 
(1911) led to the conclusion that the species was probably now. 
Specimens were then sent to the senior author who also was of the 
opinion that it was a new species. The sheep from which this ma- 
terial was collected were originally from the ranch of Mr. W. H. Wells 
near Resolis, Colorado, and specimens of the nematode here described 
wore collected by both of us dming the summer of 191 1 from sheep at 
Mr. Wells's ranch. The nematode was found in nearly every sheep 
examined at the ranch and was the only nematode found in the 
stomach with the exception of the stomach worm, JI;/m<mchus coitr- 
tortus. Tho new species was also found by us in sheep at the ranch 
of Mr. W. T. Kennedy near Amo, Colorado. A single specimen was 
found once in the intestine, but the occurrence of this nematode in the 
intestine was probably accidental, as the fourth stomach is evidently 
the normal location. In Colorado the greatest number of Ostertagia 
found in a single sheep was 7'-> and the greatest number of Ihrmonclmx 
contortus, 537. Usually there were less than a dozen of each. This 
comparative freedom from infection with nematodes in Colorado 
sheep is to bo attributed in part to the dry climate and in part to the 
extensive area covered in range feeding, thereby preventing concen- 
tration of infection. 

Mr. W. D. Foster of the Zoological Division, Bureau of Animal 
Industry, has called our attention to a single specimen of a nematode, 
a female, collected by him May 13, 1910, from a sheep received in 



Proceedings U.S. National Museum, Vol. 42— No. 1892. 

175 



176 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 42. 

Washington from Montana. This specimen he had been unable to 
identify with any described species. Examination shows that it is 
of the same species as that collected by us in Colorado. Ostertagia 
bullosa is therefore known to occur in two of the Rocky Mountain 
States. Two other species of this genus have been found thus far only 
in the Rocky Mountain region, namely Ostertagia marslialli and 0. 
occidentalis, these two being reported heretofore only from Montana. 
To these records may be added our finding, in 1911, at a Denver 
abattoir, of 0. marshalli in sheep from Wyoming and Utah, and of 
0. occidentalis in sheep from Wyoming. 

The new species is white when freshly collected and has the usual 
characteristics of the genus Ostertagia, but differs from other species 
of the genus in that the two ventral rays of each lateral lobe of 
the bursa are rather widely divergent, the spicules are simple and 
not split into several processes posteriorly, and the gubernaculum 
is of the same yellow-brown color as the spicules instead of being 
colorless. 

In the key given in Ransom (1911) this species runs down to 
Ostertagia trifurcata of which only the male is known. In several 
respects, however, it differs from trifurcata. The gubernaculum in 
0. trifurcata is a narrow colorless structure, whereas in 0. bullosa it is 
a yellowish-brown structure, irregularly trihedral in shape. The 
spicules in 0. trifurcata are twisted but are not curved in their long 
axis, and are divided into 3 processes at the posterior end. The 
spicules in 0. bullosa are narrow, curving, tubular structures, not 
divided at the posterior end which is acutely pointed. Each of the 
two terminal branches of the dorsal ray in 0. trifurcata has a short 
process on the outer side and one on the inner. 0. bullosa has a short 
process on the outer side, but the process on the inner side is only sug- 
gested by a slight and often indistinct bifurcation at the tip. 

The principal characters of 0. bullosa are as follows: 

OSTERTAGIA BULLOSA Ransom and Hall, 1912. 

Specific diagnosis. — Ostertagia: Male (fig. 1) about 7.3 mm. long. 
Maximum thickness 115 p just in front of bursa. Diameter of head 
17 p; diameter of body at level of nerve ring 44 to 48 p, at base of 
esophagus 68 a. Esophagus 510 to 545 p in length, surrounded by a 
nerve ring at a distance of 220 to 250 p from the anterior end. The 
excretory pore is situated about 270 p from the anterior end of the 
body. Cervical papilla? not evident. The esophagus increases in 
diameter from 16 p anteriorly to 45 or 50 p at its posterior end. The 
bursal membrane has a very distinct longitudinal striation. The 
median lobe is only slightly shorter than the lateral lobes. The lateral 
lobes are usually partly folded over each other in their ventral por- 
tions. The ventro-ventral (fig. 2, v. v.) and latero- ventral (fig. 2, 1, v.) 



no. 1892. A NEW PARASITIC NEMATODE— RANSOM AND HALL. 



177 



rays diverge considerably, which is unusual in the genus Ostertagia, 
and their tips are at least half as far apart as the tips of the latero- 
ventral and externo-lateral rays. The distance between the tips 
of the externo-lateral and medio-lateral rays is much less than that 
between the latter and the tip of the 
postero-lateral ray. Of the paired 
rays, the latero-ventral is the thickest- 
Following this in the order of size are 





Imm. 



I mm. 



\ 00 JUL. 



Fig. 1.— Osteetagia bullosa. Male and 
female. *vulva. enlarged. 

the externo-lateral (fig. 2, e.l.), 
then the medio-lateral (fig. 2, 
m. I.), the postero-lateral (fig. 
2, p. I.), and the externo-dorsal 
(fig. 2, e. d.), which are of about 
the same size, and lastly the 
ventro-ventral. The dorsal ray 
(fig. 2, d.) is about 140 <i long 
and is bifurcated 25 to 40 /j. 
from its posterior end. The 
terminal branches have each a 
small branch, sometimes re- 



Fig. 2.— Ostertagia bullosa. Posterior end of 
body of male, viewed from left side, bul., prebur- 
sal bulla; d., dorsal ray; e. d., externo-dorsal 

ray; e. i., externo-lateral ray; gub., gubernacu- duced to a mere knob, on the 

lum; I. v., latero-ventral ray; m.l., medio-lateral .. . . , » , 

ray; p. i., postero-lateral ray; sp., left spicule; outer side. i\.t times eacn or tne 
v. v., ventro-ventral ray. Enlarged. terminal branches ends in a very 

small fork and at times appears to end without forking. The spicules 
(fig. 2, sp.) are 140 to 180 p. long and 15 to 20 ;x wide at the anterior 
end. They gradualty narrow toward the posterior end, which is 
pointed, and do not fork. Usually the tips are curved but in some 
20441°— Proc.N.M.vol.42— 12 12 



178 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL.. 42. 



specimens they appear to be straight. The gubernaculum (fig. 2, 
gub.) is irregularly trihedral in shape, somewhat resembling a plow- 





100/A./ 

flg. 3.— ostektagia bullosa. tail 
offemale, viewed from left side. 
Enlarged. 

share in outline when viewed from 
the side, and prolonged into a 
short slender process anteriorly. 
Measured from the side it is about 
25 pi wide and 65 p. long. It is of 
the same yellow-brown color as 
the spicules. 

A well-marked character of this 
species is a prominent cuticular 
swelling anterior of the bursa on 
the ventral surface (fig. 2, but.). 
For some distance anterior of the 
swelling the cuticle on the ventral 
surface is somewhat thickened and at a distance of 100 to 125 // in 
front of the bursa the cuticle splits to form this swelling. When 



Fig. 4.— Ostertagia bullosa. Region of 
vulva of female, viewed from left 
side, e., egg; lab., rudimentary cutic- 
ular FLAP ANTERIOR OF VULVA; OVij. 1, 
TERMINAL PORTION OF OVIJECTOR; OVlj. 2, 
SPHINCTER OF OVIJECTOR; OVij. 3, NONMUS- 
CULAR PORTION OF OVIJECTOR; Ut., UTERUS; 

vul., vulva. Enlarged. 



no. 1892. A NEW PARASITIC NEMATODE— RANSOM AND HALL. 179 



viewed from the side, the optical section of the cuticle forming the 
ventral boundary of the swelling, is usually oval but sometimes has a 
more rectangular outline, resembling somewhat the trigger guard on 
a rifle. , The swelling is apparently filled with a clear transparent 
fluid. The prebursal papilla? are located near the lateral limits of 
tins swelling and about 15 ll in front of the anterior edge of the bursa. 
. Female (fig. 1), 8.8 to 9.8 mm. long by about 13 ll wide in the region 
of the vulva. The head measures 20 to 25 p. in diameter. At the 
nerve ring the body is 50 to 60 ll in thickness, at the base of the esoph- 
agus 70 to 80 ll, and at the anus 50 to 55 ll. The esophagus is 580 
to 620 ll long and is surrounded by a nerve ring 220 to 255 /x from the 
anterior end. The excretory pore is 265 to 320 ll from the anterior 
end. Cervical papillae not evident. The vulva (fig. 4, vul.) is trans- 
versely elongated, commonly presenting a crescentic outline with the 
convexity of the crescent directed posteriorly. At times a very 
small, rudimentary cuticular flap (fig. 4, lab.) is evident. The vulva 
is situated 1 to 1.3 mm. from the posterior end of the body. The tail 
(fig. 3) tapers posteriorly, always curving ventrally and usually 
curving more sharply near the end to form a rather open hook, which 
terminates in a slightly enlarged, rounded tip. The cuticle of the tail 
beginning in the anal region and extending to the tip is marked by 
very fine transverse striations close together. The anus is situated 
120 to 150 ll from the tip of the tail. The cuticle surrounding the 
anus is usually swollen so that a prominence appears at this point 
25 to 35 ll in diameter and 5 to 8 ll high. The combined length of the 
muscular portions of the ovijectors (fig. 4, ovij.), including the sphinc- 
ters, is 220 to 360 ll. The maximum size of the eggs (from measure- 
ments of eggs observed in the ovijectors) is 85 ll long by 65 ll wide 
(fig. 4, e.). 

Host. — Ovis aries. 

Location. — Fourth stomach. 

Localities collected. — Colorado; Montana. 

Type- specimens. — Cat. No. 16083, U.S.N .M. (Bureau of Animal 
Industry Helminthological collection); collected July 30, 1911, at 
Wells's ranch, Kesolis, Colo., by B. H. Ransom from the fourth 
stomach of a sheep. 

REFERENCE. 

Ransom, B. H. 1911. The nematodes parasitic in the alimentary tract of cattle, 
sheep, and other ruminants. Bull. 127, Bureau Animal Ind., U. S. Dep. Agr., 
Washington, 132 pp., figs. 1-152. 



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